It is known to provide a sortation system which includes a plurality of chutes which are movable along a generally continuous loop to deposit articles, such as mail articles or the like, into appropriate bins or trays positioned at a plurality of sort stations of the sortation system. As shown in FIGS. 1 and 2, each chute 2 of a sortation system typically includes a tray full detecting arm 3, which is pivotally mounted to the chutes 2 and which is pivotable about a pivot axis 3a in response to the end of the sensor arm contacting the articles or mail deposited in the tray or bin 4 (such as a flats mail tray or the like) by the chute. As the level of articles in the tray increases, the articles push the end of the sensor arm upward. As can be seen in FIG. 2, as sensor arm 3 is pushed upward, the arm may pivot and may trigger a switch when the arm has pivoted a threshold amount. The sortation system and/or chutes may be controlled to stop depositing more articles into that bin in response to the arm triggering the switch.
Also, and as shown in FIGS. 3 and 4, each sort station may include a tray detecting mechanism 5, which is operable to indicate the presence of a tray or bin 4 at the sort station via pivotable movement of a pivot arm 6, which contacts the tray and pivots as the tray is pushed into the sort station. As can be seen in FIGS. 3 and 4, the pivot arm 6 may pivot about a pivot axis 6a in response to the tray being pushed fully into the sort station, whereby a cammed surface 6b of the pivot arm may actuate a switch to indicate that the tray is present at the respective sort station.
Because the conventional tray full detecting arm and tray detecting mechanism are mechanical assemblies, they may require movable contact with the mail articles and/or trays. The tray full detecting arm may thus interfere with the mail or articles as the articles slide down the chute and into the tray, and thus may create chute jams that require operator assistance to clear so that sorting can continue. Also, the tray full detecting arm may allow the mail or articles to fill past the handle of the tray, which may present problems to an operator who has to pull and carry the trays after they have been filled. Although the tray full detecting arm typically can be adjusted, it typically cannot be lowered enough to avoid such filling conditions or concerns. Also, the conventional mechanical detecting or triggering assemblies typically utilize a limit switch that may be unreliable and may become filled or blocked with dust or the like, which may interfere with the contacts and may disable the assembly or mechanism until the limit switch is cleaned or replaced.
Therefore, there is a need in the art for a tray full sensing device and tray present sensing device which overcomes the shortcomings of the prior art.